Cover for flushing tank



FIG. 1 is a front view of my new design for a cover for a flushing tank;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is left view thereof;

FIG. 5 is right view thereof; and,

FIG. 6 is a front left perspective view thereof. 

The ornamental design for a cover for flushing tank, as shown and described. 